Small molecule toxins have been found to be epidemiologically linked to a number of protein misfolding diseases. Using arsenite (As(lll)) as a model system, the potential role of environmental toxins on altering the global protein fold in vivo will be analyzed. The mechanism of As(lll)-induced protein misfolding will be evaluated by comparing the proteins found to be misfolded in As(lll)-treated cells and proteins that are found to bind As(lll) in situ. As(lll)-induced misfolding will be further characterized by comparisons between the misfolded proteins in As(lll) treated cells and misfolded proteins in cells treated with other stress- inducing agents, allowing the mechanism of As(lll)-induced misfolding to be elucidated. Using the methods outlined in this proposal, the role of the Integrated Stress Response and AIRAP in protecting cells against As(lll) toxicity will be also be examined. This work will not only identify potential therapeutic targets for the numerous human populations predisposed to human disease by As(lll) exposure, but it will also allow for a better understanding of the role environmental toxins play in predisposing populations to protein misfolding diseases of aging and neurodegeneration. [unreadable] [unreadable] [unreadable]